All Sky Camera Revisited

[Gina]

-6.2°C  I'm satisfied! 😀

[Gina]

Done a bit more on the ASC.  Soldered the wires of a 4 core cable to the Peltier TEC and dew heater.

• Red - dew heater control -ve
• Yellow - 13.8v - dew heater +ve
• Green - 0v - TEC -ve
• Blue - Cooling control - TEC +ve

Reason for colour choice was

• Green is my power ground colour
• Yellow is 12v/13.8v standard colour
• Red represents heat
• Blue represents cold

These are the wire colours in the cable.

Edited June 21, 2020 by Gina

[Gina]

Mast now cut to length.

[Gina]

All pipes attached to ASC and cables and pipes fed thought mast fitting and though mast pipe and out of hole in the side.  Fitting and ASC pushed onto mast top.  Mast with ASC taken out to observatory and erected on north side then fastened to wall bracket.  Unfortunately, I had an accident on the way out and caught the dome on the wall of the house imparting a horrible scratch!!  I'l see how bad it looks and see if I want to but a replacement at £16 plus P&P coming to just under £21.  A bead of silicone sealant was put round the bottom of the dome.  It should be possible to get it off if I need to.

[Gina]

"I don't believe it!!!!"  OK so Ive got the ASC operating - sort of!

[DaveL59]

oh dear Gina, not a good day then  Wonder if the knock has affected the focus?

[Gina]

It would seem so but it was only a light touch!  Guess I'll have to take it all apart again to see what's gone wrong.  I think the lens must have moved relative to the camera.  Might be able to see if I put a ladder up against the observatory wall but with all the rain we've had lately I think the ground will be too soft.

I'm not touching it anymore tonight - had enough of it for today!!!

Edited June 21, 2020 by Gina

[DaveL59]

could be the sensor board has shifted a touch too if its cropping the image on one side. Defo leave it for another day tho, a break from it can help get focus on the issue with fresh mind/eyes  

[Gina]

Oh yes, I know when I've have enough of something!  I always find it best to stop and leave it and do something else.

[Gina]

I may be able to access the ASC from inside the scope room with the roof open with steps.  I'll look tomorrow.

[Gina]

Looked at ASC and can see the problem - lens is crooked, not properly down onto the camera.  To difficult to fix in situ so will have to bring it indoors.  Might remove it from the mast outdoors to avoid more possible damage to the dome.

[Gina]

Now have the ASC safely indoors ready to work on, leaving mast pipe outdoors on the grass.  First job is to get the dome off then I can see if I can push the lens down into the camera.

[Gina]

Eventually managed to get the dome off!!  That Gorilla silicone sealant is strong stuff!!  Had to get a hacksaw to it.  Once the dome was off I easily pushed the lens back in place.  In a while I get the electronics unit and test the ASC.  Need a break first.

[Gina]

Testing ASC - the FoV is now fine but the focus is still out so I'll have to adjust it.

[Gina]

Re-focused - think this might do.

[Gina]

Dome sealed back on.  I'll leave the sealant to go off and take it out later.

[Gina]

I've been at this stage before and the feeling of déjà vu is overpowering!!

[Gina]

All set up outside, power on and ready to test!  Oh dear, here we go again.  If the focus is out I think I shall cry!!!

[Gina]

PHEW!!!  Seems fine!  WOW!!  That bunch of white specs just above half way up is the dome damage shining in the sunlight.

[DaveL59]

well done!

worrying tho that the lens shifted tho even what can seem like a small glancing tap can have quite an effect once momentum of the lens mass and the ASC unit are taken into account. Fingers crossed it all stays settled and gives great results, image and of course water resistance  

[Gina]

Thank you.  Unless we get a bad earthquake the focus should stay put now.  Water resistance remains to be seen.

[Gina]

ASC seems to be working well.  This is with minimal cooling (5v) and it wants a bit more but not really the full 13.8v.  Think I may provide an intermediate setting.

[Kev M]

Wow...that's good

[Gina]

The above showed a sensor temperature of 3.5°C.  With full cooling it's reached -13.5°C and still going down.  This is the image.  Still showing some hot pixels.

[Gina]

I think the LOW cooling level could be increased as the sensor temperature now is 12.6°C rather than adding another buck converter and power MOSFET etc. to control it.  The LOW cooling voltage is supplied from its own buck converter, separate from the 5v supply for the RPi, so I only have to turn up the output voltage.